Place a 1/8-inch steel plate directly onto the cabinet the granite will be installed on. Line up the one edge of the steel plate with the edge of the cabinet the granite will not be overhanging. The other side of the steel plate should extend out over the cabinets to within 4 inches of where the granite will end.
Drill holes in the steel plate with a steel bit where the plate will line up with the cabinet's stiles, or edge. Screw the plate directly onto the cabinet where it meets the cabinet's edge for support.
Apply epoxy to the steel plate. Make a large X over the plate, and then trace the edge of the plate with a solid line of epoxy. Lift the granite slab over the plate and settle it into place. The steel will extend beneath the slab and hold it in place, the epoxy will harden within 24 hours and will permanently fix the plate to the granite.